It is known to weld a reinforcement member made of a plate member to the inner or outer panel of the automotive door so as to form a frame structure having a closed vertical cross section inside the door as disclosed, for instance, in Japanese patent laid open (kokai) publication No. 62-103222 for reinforcing the automotive door against side impacts. This conventional structure is intended as a reinforcement for minimizing lateral deformation when subjected to external side impacts.
However, this structure does not take into account any side impact which may be applied from inside the passenger compartment.